Fuel injection pump



Patented Mar. 5, 1940 UNITED STATES 2,192,372 FUEL INJECTION PUMP TracyV. Buckwaiter, Canton, Ohio, assignor to The Timken Roller BearingCompany, Canton,

Ohio, a corporation of Ohio Application November 18, 1937, Serial No.175,234 1 Claims.

This invention relates to fuel injection pumps of the type wherein thepump plunger is provided with inlet and overflow ports that are locatedadjacent to each other and communicate 5 with a common fuel supplypassageway and the.

pump plunger, at a predetermined point of its pressure stroke, by-passesfuel from the pressure space in the pump cylinder to said fuel supplypassageway through said overfiow port, thereby relieving the pressure insaid pressure space and terminating the fuel delivery.

In the above type of pump, the by-passed fuel enters the fuel supplypassageway under considerable pressure and thus places the fuel thereinadjacent to the inlet and overfiow ports in a violent state of commotionor turbulence, thereby interfering with the flow of fuel into thepressure space of the cylinder on the following suction stroke of theplunger and thus causing the pump to deliver an insuificient quantity offuel. The principal object of the present invention is to provideimproved means for preventing such interference with the filling of thepressure space of the cylinder on the suction stroke of the plunger.Other objects are cheapness and simplicity of construction and compactof design. The invention consists in the fuel injection pump and theparts and combinations and arrangements of parts hereinafter describedand claimed.

In the accompanying drawing, which forms part of this specification andwherein like symbols refer to like parts wherever they occur,

Fig. 1 is a horizontal section through a fuel injection pump embodyingmy invention, the section being taken on the line II of Fig. 2,

Fig. 2 is a vertical transverse section through said pump at one of thecylinders on the line 2-2 in Fig.1,

Fig. 3 is a view similar to Fig. 1 illustrating a modified form of theinvention.

Referring to the accompanying drawing, my.

invention is illustrated in connection with a multi-cylinder fuelinjection pump for a multicylinder internal combustion engine of thecompression ignition type. Said pump comprises a suitable housing Ihaving a plurality of vertical bores 2 therein that are spaced apartlongitudinally thereof and have enlarged lower end portions 3 adapted toreceive tappet cups 4 that are engaged at their lower ends by cams ortappets 5 on a cam shaft 6 located in a longitudinal chamber *1 providedtherefor in the bottom of said housing.-

Mounted in each of the vertical bores 2 of u the pump housing I is apump cylinder 8, which contains a piston or plunger 9 and has anenlarged upper end portion l0 thatrests on an annularseat II providedtherefor in the upper portion of said bore. A tubular member l2 rests onthe upper end of the pump cylinder 8 and is provided at its upper endwith a seat l3 for a suitable fuel discharge valve l4. Threaded into theupper end of the bore 2 is a tubular fitting or shell 15, which holdsthe valve seat member 12 down on the upper end of the pump cylinder andthe latter down on its 'seat in said bore and is provided at its upperend with a space for a coil spring l6 that normally holds the fuel discharge valve l4 against the seat 13 provided therefor at the upper endof said member. A suitable fuel discharge pipe I! is connected to theupper end of the tubular fitting 0r shell l5 by means of a cap l8threaded on the upper end thereof. I

The pump housing I is provided on one side of the pump cylinders with alongitudinal fuel passageway I9 which opens into all of said cylindersthrough inlet ports in that side there-,- of. Said housing is likewiseprovided on the opposite sides of the pump cylinders with a longitudinalfuel passageway 2| that also opens in all of said cylinders throughoverflow ports 22 in that side thereof. As shown in the drawing, the twospaced parallel fuel passageways l9 and 2| and the ports communicatingtherewith are preferably located at the same level.

" Each plunger 9 is preferably provided with an annular groove 23 thatcommunicates through a longitudinal groove 24 with the pressure space ofthe cylinder and has an inclined or helical edge 25, whereby thedelivery stroke of the plunger may be regulated by turning it in itscylinder to vary the point in the pressure stroke of the plunger inwhich the overflow portv 22 is placed in communication with saidpressure space through the grooves 23 and 24 to relieve the pressure insaid space and thereby permit the delivery valve I4 to seat andterminate the fuel delivery. By this arrangement, delivery of the fuelbegins as soon as the plunger stroke covers the ports 20 and 22 and endsas soon as the helical. upper edge 25 of the groove 23 in the plungeropens the overflow port 22 and relieves the pressure in the space abovesaid plunger.

The mechanism for turning the plungers on their axes to vary the amountof fuel delivered thereby preferably comprises axially alined upper andlowerdriving and driven sleeves 26 and 21 mounted onthe lower endportions of the cylinders and plungers, respectively, and a rack rod 28mounted for axial sliding movement in a horizontal bore that extendslongitudinally of thepump from end to end thereof on one side of thecylinders and cooperates with gears 29 on the upper ends of therespective driving sleeves. The upper or driving sleeve 26 for eachplunger is rotatably mounted on the lower end of the cylinder therefor;and the lower or driven sleeve 21 has a non-rotary connection with saidplunger comprising a flatsided portion 3|) thereof that fits a similarlyshaped opening in the lower end of said lower sleeve. The drivingconnection between the driving sleeve 26 and the driven "sleeve 21preferably comprises upwardly extending oppositely disposed tongues 3|on the driven sleeve that fits within downwardly opening diametricallyopposed notches 32 fitted therefor in the driving sleeve, therebypermitting relative axial movement of the two sleeves but preventingrelative rotary movement thereof.

Surrounding the-driving and driven sleeves for each plunger is a helicalcompression spring 33 that serves to retract said plunger and to holdthe driven sleeve 21 upwardly in the tappet receiving portion of thevertical bore 2 in the pump housing. The tappet cup 4 is spacedoutwardly from the driven sleeve 21 so as .to accommodate the pistonretracting spring 33. A washer 33a supports the driving sleeve 26 belowthe gear 29 thereon and is held against an annular shoulder providedtherefor in the vertical housing bore 2 by means of the spring 33. Theplunger is provided below the bottom of the lower portion of the, drivensleeve 21 with an annular groove 34 and terminates below said groove ina flat-sided head portion 35. The lower end of the piston retractingspring 33 is supported upon an annular seat provided therefor on acircular block 3511 having an opening therein whose upper portion snuglyreceives the grooved portion 34 of the plunger and whose lower portionis widened to receive the head 35 at the lower end of the plunger. Thisblock seats on the bottom of the tappet cup 4 and 38 threaded thereinthat is adapted to receive and support the threaded end of a fuel'inletor supply pipe or conduit 39 which le'ads from a suitable fuel supplypump or other source of fuel supply (not shown). The'threaded opening 31at the opposite end of said housing also has a sleeve 40 threadedtherein that is adapted to receive and support the threaded 'end' of apipe or conduit 4| which is preferably provided with a check or reliefvalve 42 and is adapted to return to the fuel pump or supply fuel inexcess of that discharged through the delivery valves |4.

By the arrangement described, the fuel flows from the single supply pipe39 into the adjacent ends of the two longitudinal fuel passageways 9 and2| where it is separated into two separate streams that are joinedtogether upon leaving the ends of said passageways and enter the returnpipe 4| in the form of a single stream. With this arrangement of fuelfeed, any violent com-- motion or disturbance created in the fuel streamin the fuel passageway 2| by the fuel by-passed I or discharged intosaid stream from the overflow ports 22 is segregated from the inletports 29 and thusdoes not interfere with the flow of the fuel into theinlet ports. The continuous flow of fresh fuel through the fuelpassageway 2| which com-' municates with the overflow ports 22 alsotends to smooth away or diminish any turbulence of fuel in saidpassageway and thereby minimize the effect of such disturbance on thefuel drawn into the cylinder through said overflow ports; thiscontinuous fiow of fresh fuel also serves to carry away and break up anybubbles created by the return flow of the surplus orby-passed fuel.

In the modified construction shown in Fig. 3,

the spaced parallel fuel passageways |9a and 2|a terminate at theendmost pump cylinders and the pump housing is provided with fuelchambers 43 that communicate with both of said passageways. A fuelsupplyconduit 39a opens into one of said fuel chambers preferablysubstantially I with the overflow or .by-pass ports in said cylinders.This construction operates in substantially the same manner as theconstruction shown in Fig. 1 to prevent the disturbance created in thefuel stream by the by-passed fuel from interfering with the filling ofthe pressure spaces in the 1 pump cylinders.

What I claim is: 1. A fuel injection pump comprising a plurality ofcylinders spaced apart lengthwise of said pump,

plungers reciprocating in the respective cylinders,

said pump having two longitudinal fuel passageways spaced apart onopposite-sides of said cylinders, said cylinders having inlet portstherein communicating with one of said fuel passageways and overflowports communicating with the other of said passageways, a single fuelsupply conduit opening into both of said passageways at one end thereof,and a single fuel outlet conduit leading from both of said passagewaysat the other end thereof.

2. A-fuel injection pump comprising a plurality of cylinders spacedapart lengthwise of said pump, plungers reciprocating in the respectivecylinders, said pump having two longitudinal fuel passageways spacedapart on opposite sides of said cylinders, said cylinders having inletports therein communicating with one of said fuel passageways andoverflow ports communicating with the other of said passageways, asingle fuel supply conduit opening into both of said passageways at oneend thereof, a single fuel retum' conduit'leading from both of saidpassagewaysat the other end thereof, and a pressure control valve invsaid return conduit.

3. A fuel injection pump comprising a plurality of cylinders spacedapart lengthwise ofsaid pump, plungers reciprocating in the respectivecylinders, said pump having single openings inits opposite ends and twolongitudinal fuel passageways. spaced apart on opposite sides of saidcylinders andboth communicating at one end with one of said openings andat the other end with the other of said openings, said cylinders havinginlet ports therein communicating with one of said fuel pa'ssageways andoverflow ports communicating with the other of said fuel passageways, asingle fuel supply conduit opening into the single opening at one end ofsaid pump, and" a single fuel return conduit leading from the singleopening at the other end of said pump.

4. A fuel injection pump comprising a, plurality of pump cylindersspaced apart lengthwise of said pump, said pump having a fuel inletchamber partially surrounding the cylinder at one end thereof, a fueloutlet chamber partially surrounding the cylinder at. the opposite endthereof and two spaced longitudinal passageways extending from chamberto chamber on opposite sides of the remaining cylinders, said endmostcylinders having fuel inlet and overflow ports communicating with the,chambers adjacent thereto, and said remaining cylinders having fuelinlet and overflow ports communicating with the respective fuelpassageways, a fuel supply conduit leading to said fuel inlet' chamber,and a fuel return outlet conduit leading from said fuel,

outlet chamber.

5. A fuel injection pump comprising a pinrality of pump cylinders spacedapart lengthwise of said pump, said pump having a fuel inlet chamberpartially surrounding the cylinder at one end thereof, a fuel outletchamber partially surrounding the cylinder at the opposite end thereofand two spaced longitudinal fuel passageways extending from chamber tochamber on opposite sides of the intermediate cylinders, said endmostcylinders having fuel inlet and overflow ports com- ,municating with thefuel chambers adjacent thereto, and said intermediate cylinders havingfuel inlet and overflow ports communicating with the respective fuelpassageways, a fuel supply conduit leading to said fuel inlet chamberand a fuel return conduit leading from said fuel outlet chamber, saidfuel inlet conduit opening into said fuel inletv chamber substantiallyin line with the fuel passageway that communicates with said fuel inletports and said fuel return con-

